Method of making shrouded poppet valves



Feb. 11, 1947. OVA 2,415,606

METHOD OF MAKING SHROUDED POPPET VALVES Filed Dec. 31, 1943 2 Sheets-Sheet 1 Feb. 11, 1947.

L. P. NOVAK METHOD OF MAKING SHROUDED POPPET VALVES Filed Dec. 31, 1943 Shee ts-Sheet 2 Patented Feb. ii, 194':

METHOD OF MAKING SHROUDED POPPET VALVES Louis Philip Novak, Cleveland, Ohio, assignor to Thompson Products, Inc., Cleveland, Ohio a corporation of Ohio Application December 31, 1943, Serial No. 516,345 3 Claims. (Cl. 29-156.?)

My invention relates to a method of making a shrouded poppet valve for internal combustion engines.

In general, the object oi my invention is to provide a new method for making shrouded valves. which will save time and material and will allow for the use of mor corrosion-resistant material for the shroud.

In making the ordinary shrouded valve, it has been customary to extrude the valve to the shroud diameter so that when the stem part is machined,

there will be sumcient material left under the,

head to machine out the shroud. This means that there must be a much larger diameter provided for in the stem when it is extruded in order to allow for the shroud, and the greater portion oij this stem material must then be machined away to form the shroud.

In accordance with my improved process, the valve is extruded to nubbin size, that is, the same size as a valve without a shroud, and then a corrosion-resistant alloy is puddled or welded intimately to the stem at the shroud zone, and thereafter the valve stem is machined in, the usual way, but with considerable saving of material and time, to form the shroud whose tip is composed in greater part or the corrosion-resistant'material.

My invention is of particular utility in connection with hollow poppet steel valves, such as the type oi valve disclosed in McBride et al. Patent No. 1,984,751, dated December 18, 1934. A valve of this type to which my invention would Figure 3 shows the form after machining and reaming to enlarge the stem cavity and produce the head cavity;

Figures 4 and5 show the form after subjection of the form of Figure 3 to hammer dies for constriction of the stem;

Figure 6 shows the trusion operation;

Figure! shows the form after the second eutrusion operation;

- Figure 8 shows theiorm after further extrusion and lengthening of the stem, and after a groove has been cut in the stem adiacentthe neck of the blank;

Figure 9 shows the form after corrosionresistant material has been applied in the groove;

Figure 10 shows the form after drilling of the stem and machining to form the'embryo shroud;

Figure 11 shows the form after extrusion oi the enlarged nubbin on the end of the stem to close the stem cavity;

Figure 12 shows the finished valve: and

Figure 13 is a section on plane I LQIII 'E EIa or stem 5 and head H resulting from the forging be applied, could be successively formed substantially in accordance with the process disclosed in this patent, but, before the drilling operation oi the valve stem, a circumferential groove is' formed in the stem adjacent to the valve head into which groove the corrosion-resistant material for the shroud is applied. Thereafter, the' stem is drilled to form the stem cavity to meet the head cavity and the stem is machined to form the embryo shroud, whereafter the stem is ex- I I truded for lengthening thereof and closure of the stem cavity, and then by a final machining operation the finished valve is produced with the noncorrosive material forming an integral part of the shroud. 7

On the drawings, the various figures show the various formation steps of avalve from a billet of suitable metal.

Figure 1 shows the embryo valve afterthe first forging operation;

Figure 2 is the form after piercing tor the embryo stem cavity;

of a billet of suitable metal such as austenitic steel, while Figure 2 shows the iormlaiter iur- .ther forging and extrusion to and piercing to provide thestem cavity it.

Figure 3 shows the form resulting from machining or reaming to enlarge the stem cavity and to form the head cavity ii, this cavity it being substantially the same size as in the tinished .valve.

Figures 4 and 5 result from successive er= die treatment to produce the restriction i2. and

resulting of the stem to the diameter of the restriction l2, and the resulting contraction in diameter of the stem cavity l0. After a second extrusion operation, the stem is contracted toentirely close the stem bore to formsubstantially a solid stem' as shown in Figure 7. Further extrusion results in lengthening of the stem and reduction of the stemsdiameter to the form shown in Figure 8.

In the form shown onrFisure 8, the stem is of nubbin size, that is, substantially the size it would be for the production of an unshrouded valve. In accordance with my invention, this stem is now machined to provide thecircumferen tial groove M adjacent to the neck part i3 at the base of the head H. Corrosion-resistant metal is then intimately paddled or welded into form after the first 'exlengthen the stem,

the groove II to become integral with the stem and build up a. band or ring of larger diameter than the nubbin diameter of the stem S. Any suitable corrosion-resistant material may be used, examples of which are nickel, chromium and iron alloys; nickel, molybdenum and iron alloys; non-ferrous nickel-chromium alloys; and chromium-tungsten alloys. Figure 9 shows the band or ring l5 located in the zone where the shroud is to be formed.

After application of the corrosion-resistant material the stem is drilled to provide the cavity H) which merges in the head cavity I I, and then the valve is machined in a lathe or otherwise to reduce the intermediate part 16 to substantially finished valve stem diameter while leaving a nubbin end of the same diameter as the stem of Figure 9. The machining of the stem along the zone'of the corrosion-resistant material l5 will leave-the base portion ll'l of the shroud from which the corrosion-resistant material extends for forming the shroud end 18. During this machining operation, the head H and the neck part l3 are trimmed down closer to finished dimensions and the boss I9 may be left on the head for centering of the valve for further machining operation to its finished form. r

After the machining operation resulting in the 4 form shown on Figure 10, the valve can be filled ,form is now placed in a lathe for machining to the finished form shown on Figure 12. During this fin'al machining operation, the shroud part formed by the base i1 and the end l8 of corrosion-resista'nt material is under-cut as indicated at and trimmed down to form the completed shroud. During this final machining operation,

shroud zone is less than shroud diameter, then providing acircumferentiai groove in the shank at the shroud zone' and applying corrosion-resistant material in said groove to an outer diameter greater than that of the embryo shank,

, then machining the shank end to form the valve stem, machining the corrosion-resistant metal to a shroud shape, and undercutting the base of the shroud to form a skirted shroud with said corsistant metal onto the shank of the embryo valve adjacent the head to locally build up the shank diameter to greater than shroud diameter, machining the end of the shank to finished valve stem diameter, machining the outside of the corrosion-resistant metal to shroud shape, and undercutting the base of the shroud to form a skirted shroud with said corrosion-resistant meta-i forming the skirted end of the shroud;

3. The "method of providing a shroud on a poppet valve of the type in which a cavity in the stem communicates with a cavity in the head, which comprises forming the valve by extrusion and contraction up to the embryo form in which the groove 2| is formed near the tip end of the stem for receiving retainer lock structure (not shown) when the valve is put into service. During the final finishing operation the head and its neck part are also turned down tofinal dimensions and the centering boss I9 is cut away.

When machining the embryo valve to the form shown on Figure 10, a circumferential groove or charmel 22 may be cut in the head to receive a ring of hard corrosion-resistant material 23. This material maybe puddled or welded intimately in the groove 22, as shown in Figure 11, and then, when the valve is turned down to its final form during the final machining operation,

this material will form a heat and corrosion-,

resistant seating face for the valve, as shown on Figure 12. t

It will be apparent from the above description that shrouded valves can be produced with considerable saving of material and time and with a. resulting shroud or skirt at the neck of the valve composed in greater part of the corrosionresistant material. This corrosion resistant shroud is desirable in exhaust valves to deflect the exhaust gases away from the valve stem and is effective to increase the life of the valve.

valve which comprises forming a valve head with an embryo shank thereon whose diameter at the the shank cavity is closed to form a solid shank of a diameter less than the diameter which would be necessary if the shank were to be machined to form an integral shroud, then forming a circumf erential groove in the shank, then puddling corrosion-resistant material onto the shank in said groove to locally build up a ring to an outer diameter slightly greater than shroud diameter, reducing the end of the shank to substantially finished valve stem diameter, machining the corrosion-resistant metal to a shroud shape, and undercutting the base of the shroud to form a skirted shroud with said corrosion-resistant The following references are of record in the file of this patent: L

UNITED STATES PATENTS Number Name Date 2,127,929 Miller Aug. 23, 1938 1,136,408 Cobb Apr. 20, 1915 1,235,344 Lindemann July 31, 1917 933,698 Crook Sept. 7, 1909 1,106,064 Thompson Aug. 4, 1914 2,135,966 Daisley Nov. 8, 1938 1,984,751 McBride Dec. 18, 1934 2,057,858 Sullins Oct. 20, 1936 1,106,054 Thompson Aug. 4, 1914 I 1,583,432 Wilcox May 4, 1926 1,727,621 Taub Sept. 10, 1929 1,789,374 Sullivan Jan. 20, 1931 2,032,162 Zahodiakin Feb. 25, 1936 2,165,871 Rector July 11, 1939 2,277,356 Sargent Mar. 24, 1942 FOREIGN PATENTS Number Country Date British Aug. 4, 1936 

